There are situations where people need to convey heavy or bulky objects, e.g. suitcases, up or down uneven slopes, such as staircases when no elevator is available. Dragging such heavy objects up or down a flight of stairs can be very difficult.
Conventional suitcases usually have wheels on the bottom to ease the movement of the suitcase on a flat surface. However, such configured wheels are not suitable for manoeuvring the suitcases over the edges of staircases.
U.S. Pat. No. 6,938,740 discloses a suitcase that has a plurality of rollers mounted on the back panel of the suitcase to assist in pulling the suitcase up a staircase and a handbrake to stop the movement of the suitcase on the stairs by frictionally engaging brake pads with the rollers. However, this disclosed suitcase has certain disadvantages. Firstly, the friction brake is not consistently reliable, due to wear and tear of the brake pads. Secondly, the brake is ineffective when the suitcase is out of the reach of a user. Accidental release of such a suitcase at an upper staircase would endanger the lives of people who happen to be in the way of the suitcase rolling down the staircase.
Therefore, there is an imperative need for a device for conveying, objects on uneven slopes conveniently and safely.